No Eng Power / Computer issues?

[discovervaacd]

have had engine work "head gasket", "new coil packs", TPS, air flow meter.. wires plugs. The tech attempted to wipe the computer and in performing the road test he was able to complete "test A, and B" but when conducting C @ 30mph engine starts sputtering and misfiring but the only code is P1590. I have the 3 amigos as well, interested to know if they will cause the engine to run abnormal? Tech is using a ODBII tool, and the throttle when fully open is only indicating 77%, should it be indictating 100%. Have checked the Crank Signal, Veh Speed Sensor and TPS. Eng will idle 'great'.. power brake to 4-5K rpm... but when driving "flooring" NO power runs smoothly under 30mph but again NO power.. Is there a test that can be conducted to check the computer, will i need some other resets that can't be done w/o going to the dealer?

Appreciate assistance.

 

[joey]

Ok, first things first... I don't think I Have read in any of your posts what year, but I will make a sad assumption that you have a D2 with a 4.0 engine.

I hate Assuming anything.

IIRC you had coolant issues causing you to change a head gasket.

The P1590 is rough road signal, normally indicates a bad MAF or just plan dirty.

The three Amigos will not cause any rough engine issues that I know of, may cause brake issues if the the ABS is not working up to par.

Under load not running I would look at your CATS as they may have been damaged from the coolant.

You can also unplug the MAF sensor and see if this changes things. The IAC or TPS can also be unplugged and vehicle driven... do them one at a time to test for issues.

VSS on a D2 acts only with the ABS sensor to get a good speed since of the vehicle.

I would call, but sadly have a nasty headache. If what I say doesn't work, try contacting Will Tillery @ Roverguy.com he is in Virginia as well, very knowledgeable and highly recommended.

 

[discovervaacd]

discovervaacd more engine issues

Thanks Joey,
I apoligize, first it is a D2 2001 4.0L.. I have attempted to use this forum before but I think the post that I had have been deleted.
Your assumptions are correct I did have a coolant issue, and with that I have had the CAT's as well as the previously noted head gaskets, replaced so that was addressed.
If I have you correctly, I will disconnect the MAF and attempt to drive the vehicle. I have two MAF but there may be an issue w/ the wiring.. was acting funny when the wires we moved around before "will re check".
If no change I will disconnect the TPS and drive the vehicle and see what that does.
What do you feel about no codes being displayed other than 1590?
What about the 77% indication w/ the pedal "floored" should the indication be 100%?
Lastly, am I correct in assuming that in your opinion D2 VSS does not have an effect on this problem?

oh, appreciate your expertise.

 

[joey]

You are correct on the unplugging and driving hope you find the issue there.

If a wiring issue this could be a mouse problem check all wires that are visible.

No codes other than 1590, this could just be a MAF sensor issue or wiring...

Not sure on the 77% part, could be anything from normal to the builder had one to many quarts at the pub the night before your part was made.

Correct the VSS On a D2 doesn't effect the D2 like it will the D1... on the D1 it will cause all kinds of fun issues.